Mapping uplink acknowledgement resource based on downlink control channel

ABSTRACT

Techniques for determining an uplink (UL) acknowledgment (ACK) resource based on a physical downlink control channel (PDCCH) carrying a resource allocation for a user equipment (UE) are disclosed. The mapping between the UL ACK resource and the PDCCH may be implicit, which may reduce overhead. The UL ACK resource may be associated with a time-varying cyclic shift of a base sequence used by the UE to send ACK information. The UE may send the ACK information based on the time-varying cyclic shift of the base sequence, which may randomize interference.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

The present Application for Patent is a continuation of U.S. patentapplication Ser. No. 12/019,909, entitled “Mapping UplinkAcknowledgement Transmission Based On Downlink Virtual Resource Blocks,”allowed Apr. 2, 2012, which claims priority to Provisional ApplicationNo. 60/886,889, entitled “Reduced ACK Overhead for Orthogonal Systems,”filed Jan. 26, 2007, and to Provisional Application No. 60/888,233,entitled “Mapping of UL ACK Transmission Based Upon DL VRBs,” filed Feb.5, 2007, all assigned to the assignee hereof and hereby expresslyincorporated by reference herein.

FIELD OF INVENTION

The present disclosure relates generally to communication, and morespecifically to techniques for sending acknowledgement information in awireless communication system.

BACKGROUND

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, data, and so on. Thesesystems may be multiple-access systems capable of supportingcommunication with multiple users by sharing the available systemresources (e.g., bandwidth and transmit power). Examples of suchmultiple-access systems include code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, and orthogonal frequencydivision multiple access (OFDMA) systems.

Generally, a wireless multiple-access communication system cansimultaneously support communication for multiple wireless terminals.Each terminal communicates with one or more base stations viatransmissions on the forward and reverse links. The forward link (ordownlink) refers to the communication link from the base stations to theterminals, and the reverse link (or uplink) refers to the communicationlink from the terminals to the base stations. This communication linkmay be established via a single-in-single-out, multiple-in-single-out ora multiple-in-multiple-out (MIMO) system.

Universal Mobile Telecommunications System (UMTS) is one of thethird-generation (3G) cell phone technologies. UTRAN, short for UMTSTerrestrial Radio Access Network, is a collective term for the Node-B'sand Radio Network Controllers which make up the UMTS radio accessnetwork. This communications network can carry many traffic types fromreal-time Circuit Switched to IP based Packet Switched. The UTRAN allowsconnectivity between the UE (user equipment) and the core network. TheUTRAN contains the base stations, which are called Node Bs, and RadioNetwork Controllers (RNC). The RNC provides control functionalities forone or more Node Bs. A Node B and an RNC can be the same device,although typical implementations have a separate RNC located in acentral office serving multiple Node B's. Despite the fact that they donot have to be physically separated, there is a logical interfacebetween them known as the Iub. The RNC and its corresponding Node Bs arecalled the Radio Network Subsystem (RNS). There can be more than one RNSpresent in an UTRAN.

3GPP LTE (Long Term Evolution) is the name given to a project within theThird Generation Partnership Project (3GPP) to improve the UMTS mobilephone standard to cope with future requirements. Goals include improvingefficiency, lowering costs, improving services, making use of newspectrum opportunities, and better integration with other openstandards. The LTE project is not a standard, but it will result in thenew evolved release 8 of the UMTS standard, including mostly or whollyextensions and modifications of the UMTS system.

In most orthogonal systems with Automatic Repeat (ARQ), the uplink (UL)acknowledgement (ACK) is implicitly mapped on correspondingtime/frequency/code resources depending on the downlink (DL) packetlocation in time/freq/code. The one-to-one mapping is usually linked toeach minimum allocation of virtual resource block (VRB), with eachpacket containing multiple VRBs. This implies that for each packet, auser equipment (UE) has several instances of ACKs available fortransmission (reserved resources), one corresponding to each VRBcontained within the packet. This may lead to large overheads,especially when the packets span multiple VRBs. For instance, with onecyclic shift in pre-assigned UL physical resource block (PRB) per DLVRB. Considering Six ACKs per UL PRB, an overhead on the DL can be shownto be 16.66%.

It has been suggested that one cyclic shift and resource blockcombination can be implicitly mapped per physical downlink controlchannel (PDCCH). Thus, the UL overhead would be dictated by the numberof DL assignments, which would entail 16.66% for 1.25 MHz and 4% forlarger bandwidths, assuming (4, 8, 16) DL PDCCH for (5, 10, 20) MHz.However, this approach suggests that each packet has to be scheduled,shifting overhead from the UL to the DL. This approach would not beappropriate for control-less operation. Every Voice Over IP (VoIP)packet would be scheduled by the PDCCH in a unicast manner. Should thePDCCH be addressed to multiple users by bitmap (i.e., group PDCCH) forVoIP, this approach would not work. This approach does not work forpersistent assignments, at least it is believed not without cumbersomemodifications.

SUMMARY

The following presents a simplified summary in order to provide a basicunderstanding of some aspects of the disclosed aspects. This summary isnot an extensive overview and is intended to neither identify key orcritical elements nor delineate the scope of such aspects. Its purposeis to present some concepts of the described features in a simplifiedform as a prelude to the more detailed description that is presentedlater.

The present disclosure presents various aspects of determining uplink(UL) acknowledgement (ACK) resources. In one exemplary design, a userequipment (UE) may receive a resource allocation on a physical downlinkcontrol channel (PDCCH). The resource allocation may dynamicallyschedule the UE for a data transmission on the downlink. The UE maydetermine an UL ACK resource based on the PDCCH, e.g., based on anidentity (ID) of the PDCCH, or an index of the PDCCH, or resources usedto send the PDCCH. The UL ACK resource may be associated with atime-varying cyclic shift of a base sequence (e.g., a Zadoff-Chusequence) used to send ACK information on the uplink for the datatransmission on the downlink. The UL ACK resource may further beassociated with at least one frequency resource, or at least one timeresource, or at least one code resource, or a combination thereof. TheUE may send the ACK information based on the time-varying cyclic shiftof the base sequence and the UL ACK resource. The mapping between the ULACK resource and the PDCCH may be implicit, which may reduce overhead.The use of the time-varying cyclic shift of the base sequence to sendthe ACK information may randomize interference.

To the accomplishment of the foregoing and related ends, one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative aspectsand are indicative of but a few of the various ways in which theprinciples of the aspects may be employed. Other advantages and novelfeatures will become apparent from the following detailed descriptionwhen considered in conjunction with the drawings and the disclosedaspects are intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, nature, and advantages of the present disclosure willbecome more apparent from the detailed description set forth below whentaken in conjunction with the drawings in which like referencecharacters identify correspondingly throughout and wherein:

FIG. 1 illustrates a block diagram of a communication system employing areduced overhead to map downlink (DL) resource allocations to uplink(UL) acknowledgement (ACK) locations for both dynamically andpersistently scheduled user equipment (UE);

FIG. 2 illustrates a flow diagram of a methodology for implicitlymapping based on DL virtual resource block (VRB) for dynamicallyscheduled UEs;

FIG. 3 illustrates a flow diagram of a methodology for implicitlymapping UL ACK ID for dynamically scheduled UEs and explicitly mappingfor persistently scheduled UEs;

FIG. 4 illustrates a block diagram of an access node having modules forperforming dynamic and persistent scheduling of access terminals inorder to implicitly and explicitly map corresponding UL ACK IDresponses;

FIG. 5 illustrates a block diagram of an access terminal having modulesfor receiving dynamic and persistent scheduling from an access node andresponding by implicitly or explicitly mapping a corresponding UL ACK IDresponse;

FIG. 6 illustrates a diagram of a communication system incorporating alegacy General Packet Radio Service (GPRS) core and an evolved packetcore supporting reduced overhead for UL ACK ID mapping;

FIG. 7 illustrates a diagram of a multiple access wireless communicationsystem according to one aspect for UL ACK ID mapping; and

FIG. 8 illustrates a schematic block diagram of a communication systemfor supporting UL ACK ID mapping.

DETAILED DESCRIPTION

An acknowledgment (ACK) mapping automation that reduces overhead for awireless communication systems such as UTRAN-LTE, Global System forMobile communications (GSM: originally from Groupe Spécial Mobile),High-Speed Downlink Packet Access (HSDPA), or any packet-switchedsystem, by providing a mapping of uplink (UL) location (i.e., modulationlocation in time, frequency, and code) based upon a downlink (DL)allocations. Aspects address dynamic and persistent scheduling of userequipment (EU) with a selected combination of implicit and explicitmapping.

Various aspects are now described with reference to the drawings. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofone or more aspects. It may be evident, however, that the variousaspects may be practiced without these specific details. In otherinstances, well-known structures and devices are shown in block diagramform in order to facilitate describing these aspects.

As used in this application, the terms “component”, “module”, “system”,and the like are intended to refer to a computer-related entity, eitherhardware, a combination of hardware and software, software, or softwarein execution. For example, a component may be, but is not limited tobeing, a process running on a processor, a processor, an object, anexecutable, a thread of execution, a program, and/or a computer. By wayof illustration, both an application running on a server and the servercan be a component. One or more components may reside within a processand/or thread of execution and a component may be localized on onecomputer and/or distributed between two or more computers.

The word “exemplary” is used herein to mean serving as an example,instance, or illustration. Any aspect or design described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs.

Furthermore, the one or more versions may be implemented as a method,apparatus, or article of manufacture using standard programming and/orengineering techniques to produce software, firmware, hardware, or anycombination thereof to control a computer to implement the disclosedaspects. The term “article of manufacture” (or alternatively, “computerprogram product”) as used herein is intended to encompass a computerprogram accessible from any computer-readable device, carrier, or media.For example, computer readable media can include but are not limited tomagnetic storage devices (e.g., hard disk, floppy disk, magnetic strips. . . ), optical disks (e.g., compact disk (CD), digital versatile disk(DVD) . . . ), smart cards, and flash memory devices (e.g., card,stick). Additionally it should be appreciated that a carrier wave can beemployed to carry computer-readable electronic data such as those usedin transmitting and receiving electronic mail or in accessing a networksuch as the Internet or a local area network (LAN). Of course, thoseskilled in the art will recognize many modifications may be made to thisconfiguration without departing from the scope of the disclosed aspects.

Various aspects will be presented in terms of systems that may include anumber of components, modules, and the like. It is to be understood andappreciated that the various systems may include additional components,modules, etc. and/or may not include all of the components, modules,etc. discussed in connection with the figures. A combination of theseapproaches may also be used. The various aspects disclosed herein can beperformed on electrical devices including devices that utilize touchscreen display technologies and/or mouse-and-keyboard type interfaces.Examples of such devices include computers (desktop and mobile), smartphones, personal digital assistants (PDAs), and other electronic devicesboth wired and wireless.

Referring initially to FIG. 1, in one aspect, a communication system 10includes an evolved Universal Mobile Telecommunications System (UMTS)Terrestrial Radio Access Network (E-UTRAN) 12 that incorporates an ACKmapping automation 14 between at last one radio access network (RAN),depicted as an evolved base node (eNode B) 16 and a user equipment (UE)device 18. In the illustrative version, the UE device 18 is beingdynamically scheduled via downlink (DL) 20 for communication on anuplink (UL) 22. The eNode B 16 is also in communication with a UE device24 that is being persistently scheduled. The E-TRAN 12 also includeseNode Bs 26, 28.

The eNode Bs 16, 26, 28 provide an UMTS Terrestrial Radio Access(E-UTRA) user plane and control plane (RRC) protocol terminationstowards the UEs 18, 24. The user plane can comprise of 3GPP (3rdGeneration Partnership Project) Packet Data Convergence Protocol (PDCP),radio link control (RLC), medium access control (MAC) and physical layercontrol (PHY). The eNode Bs 16, 26, 28 are interconnected with eachother by means of X2 interface (“X2”). The eNode Bs 16, 26, 28 are alsoconnected by means of an S1 interface (“S1”) to an EPC (Evolved PacketCore), more specifically to mobility management entities/servinggateways (MME/S-GW) 30, 32 connected to a data packet network 34. The S1interface supports a many-to-many relation between MMEs/S-GW 26, 28 andeNode Bs 16, 26, 28.

The eNode Bs 16, 26, 28 host the following functions: radio resourcemanagement: radio bearer control, radio admission control, connectionmobility control, dynamic allocation of resources to UEs in both uplinkand downlink (scheduling); IP header compression and encryption of userdata stream; selection of an MME at UE attachment; routing of user planedata towards serving gateway; scheduling and transmission of pagingmessages (originated from the MME); scheduling and transmission ofbroadcast information; and measurement and measurement reportingconfiguration for mobility and scheduling.

The MME hosts the following functions: distribution of paging messagesto the eNodes Bs 16, 26, 28; security control; idle state mobilitycontrol; System Architecture Evolution (SAE) bearer control; cipheringand integrity protection of Non-Access Stratum (NAS) signaling. TheServing Gateway hosts the following functions termination of U-planepackets for paging reasons and switching of U-plane for support of UEmobility.

The DL 20 from the eNode B 16 includes a plurality of communicationchannels relevant to download allocation that should be mapped to uplinklocation(s) for ACK discussed below, including a Physical DownlinkShared Channel (PDSCH) 38, Physical Downlink Control Channel (PDCCH) 40,virtual resource block (VRB) 42, and physical broadcast channel (P-BCH)44.

Three different types of physical (PHY) channels are defined for the LTEdownlink 20. One common characteristic of physical channels is that theyall convey information from higher layers in the LTE stack. This is incontrast to physical signals, which convey information that is usedexclusively within the PHY layer.

LTE DL physical channels are Physical Downlink Shared Channel (PDSCH)38, Physical Downlink Control Channel (PDCCH) 40, and Common ControlPhysical Channel (CCPCH) (not shown). Physical channels 38, 40 map totransport channels, which are service access points (SAPs) for the L2/L3layers. Each physical channel has defined algorithms for bit scrambling,modulation, layer mapping, cyclic delay diversity (CDD) precoding,resource element assignment; layer mapping and pre-coding are related toMIMO applications. A layer corresponds to a spatial multiplexingchannel.

A Broadcast Channel (BCH) 44 has a fixed format and is broadcast over anentire coverage area of a cell. A Downlink Shared Channel (DL-SCH)supports Hybrid ARQ (HARQ), supports dynamic link adaption by varyingmodulation, coding and transmit power, is suitable for transmission overentire cell coverage area, is suitable for use with beamforming,supports dynamic and semi-static resource allocation, and supportsdiscontinuous receive (DRX) for power save. A Paging Channel (PCH)supports UE DRX, requires broadcast over entire cell coverage area, andis mapped to dynamically allocated physical resources. A MulticastChannel (MCH) is required for broadcast over entire cell coverage area,supports Multicast/broadcast—single frequency network (MB-SFN), supportssemi-static resource allocation. Supported transport channels areBroadcast channel (BCH), Paging channel (PCH), Downlink shared channel(DL-SCH), and Multicast channel (MCH). Transport channels provide thefollowing functions: structure for passing data to/from higher layers, amechanism by which higher layers can configure the PHY status indicators(packet error, CQI etc.) to higher layers, and support for higher-layerpeer-to-peer signaling. Transport channels are mapped to physicalchannels as follows: BCH maps to CCPCH, although mapping to PDSCH underconsideration. PCH and DL-SCH maps to PDSCH. MCH may be mapped to PDSCH.

The source allocations indicated on the DL 20 are mapped to the UL 22,which is depicted as a particular UL ACK ID 46 of the available cyclicshifts 48. In the exemplary implementation, six of twelve frequencyresources are utilized and three time resources are utilized, providingeighteen UL ACK IDs 46. In the exemplary implementation a Zadoff-Chu(ZC) sequence is used, although it should be appreciated with thebenefit of the present disclosure that other sequences can be used.

In selecting an approach for multiple access for ACK under an orthogonalARQ system, first consider a ZC sequence of natural length N and basesequence parameter λ as shown below:

x _(λ)(k)=e ^(−j·π·λ·k) ² ^(/N) wherein (λ,N)=1

We define a cyclically shifted sequence as follows:

x _(λ)(k,a)=x _(λ)((k+a)mod N) 0≦a≦N−1

The input signal to IFFT from each UE is:

y _(i)(n,k)=s(n)·x _(λ)(k,a _(i)(n))

wherein

n=LFDM symbol index

k=Tone index

a_(i)(n)=Time varying cyclic shift for user i

s(n)=ACK modulation symbol

Therefore, for each localized frequency division multiplexing (LFDM)symbol index, user i modulates a different cyclic shift of the base ZCsequence. Such a ZC sequence hopping approach ensures that adjacent cellinterference is randomized on the control channels.

With the benefit of the present disclosure, it should be appreciatedthat there are several ways of mapping the uplink (UL) acknowledgement(ACK) ID to a downlink (DL) allocation.

(1) Implicit Mapping from DL VRB. In this structure, there is animplicit one-to-one mapping from DL virtual resource block (VRB) index(i.e., DL allocation) to UL ACK location in frequency and time-varyingcyclic shift. Consider an illustrative example in which there are mcyclic shifts of ZC sequences defined per UL resource block (RB).

i=b·m+k

k={0,1, . . . ,m−1}

i=DL VRB index={0,1, . . . ,N _(VRB)−1}

b=UL ACK RB index={0,1, . . . ,(N _(VRB) /m)−1}

Then, we define:

DL VRB index i

UL ACK RB index b (FDM)

Cyclic shift a _(i)(n) on LFDM symbol index n (CDM)

b=└i/m┘

a _(i)(n)=y _(j)((i+n)mod m)

j=Cell index

y _(j)(n)=Cell specific hopping pattern

If a UE has been allocated more than one virtual resource block (VRB),the UE uses the ACK ID that corresponds to the first VRB index. Thisscales the ACK overhead appropriately, if the minimum allocation in thesystem is more than 1 VRB.

Therefore, a generalized structure is:

N=Minimum allocation

b={0,1, . . . ,(N _(VRB)/(N _(min) ·m))−1}

DL VRB index i

UL ACK RB index b (FDM)

Cyclic shift a _(i)(n) on LFDM symbol index n (CDM)

b=└i/(N _(min) ·m)┘

The minimum allocation is signaled by the network and is applicable forall UEs. The network can control the UL ACK overhead by increasing ordecreasing the minimum allocation.

(2) Implicit Mapping from DL PDCCH. In this structure, there is animplicit one-to-one mapping from DL PDCCH index to UL ACK location infrequency and time varying cyclic shift. This structure tries tominimize the UL ACK overhead, but increases the DL PDCCH overhead sincetheoretically every packet would need to be scheduled. Further, thereare some severe drawbacks when one considers the scheduling modes beingproposed for real-time services: (a) Persistent scheduling: Withpersistent scheduling or scheduling without PDCCH, the UL ACK locationis undefined; and (b) Grouped PDCCH: If the DL PDCCH is intended to agroup of UEs, the UL ACK is no longer orthogonal.

(3) Implicit Mapping from DL VRB and DL PDCCH is a hybrid mode ofimplicit mapping operation with semi-static partitioning of UL ACKresources. A Resource A is intended for No PDCCH allocated (i.e.,Persistent Scheduling) or Grouped PDCCH. In addition, UL ACK ID is animplicit function of DL VRB ID, as discussed above at (1). A Resource Bis intended for Unicast PDCCH allocated (i.e., Dynamic Scheduling). ULACK ID is an implicit function of DL PDCCH ID, as also discussed aboveat (2). Due to a semi-static partitioning of resources, this approachdoes not completely resolve the issues, especially in a mixed servicescenario.

(4) Explicit Mapping from DL PDSCH is transmitted in-band the UL ACKlocation with DL PDSCH. The UL ACK ID requires 3-bits to 7-bits,depending on the system bandwidth. Therefore, the signaling overhead isvery small. Such a structure implies that OOK signaling should be usedon UL ACK. In particular, ACK is mapped to “+1” and NAK is mapped to“0”. This structure has complete flexibility. However, it does not allowthe eNode B to distinguish between PDCCH errors and PDSCH errors. Inthis sense, it is more suited for PDCCH-less operation or persistentscheduling.

(5) Explicit and Implicit Mapping from DL PDSCH and PDCCH is a hybridmode of explicit and implicit operation with dynamic partitioning of ULACK resources. A Resource A is intended for No PDCCH allocated (i.e.,Persistent Scheduling) and Grouped PDCCH. UL ACK ID is explicitlysignaled in DL PDSCH, as discussed above at (4). A Resource B isintended for Unicast PDCCH allocated (i.e., Dynamic Scheduling). UL ACKID is an implicit function of DL PDCCH ID, as discussed above at (2).

In FIG. 2, a methodology 100 for mapping DL allocation to UL locationimplicitly maps from a first DL VRB index to an UL ACK location (index)in frequency and time varying cyclic shift in block (block 102). If morethan one resource block is allocated, the eNode B can reassign theseresources, such as through explicit scheduling to a persistentlyscheduled UE, if the communication system supports such multiplecommunication types. The UE can then transmit the assigned set ofcyclically shifted Zadoff-Chu (ZC) sequences that vary in time withinthe transmission time interval (TTI) (block 104). The UL ACK ID is sentwith UE multiplexing under a hybrid frequency division multiplexing(FDM)—code division multiplexing (CDM) structure (block 106). The ZCsequences are modulated in accordance to the ACK modulation symbols(block 108).

With the benefit of the present disclosure, it should be appreciatedthat implicit mapping from DL VRB is the simplest structure. ACKoverhead reduction is achieved by signaling minimum allocationappropriately. Hybrid explicit and +implicit operation is the mostflexible, allowing for dynamic reuse of ACK resources.

The UL throughput difference (i.e., reuse of UL ACK resources) betweenDL VRB based implicit mapping and with hybrid explicit and implicitoperation in mixed service scenarios has certain advantages that may bedesirable in certain instances.

In summary, implicit mapping between DL VRB allocation and UL ACK ID canserve as a desirable baseline in an exemplary implementation. Multipleaccess among different ACKs can be realized with hybrid frequencydivision multiplexing (FDM) and code division multiplexing (CDM)structure for UE multiplexing. Each UE is assigned a set of cyclicallyshifted ZC sequences, which varies in time within the TTI and isequivalent to ZC sequence hopping. The varying of time of the ZCsequences are modulated by ACK modulation symbols.

In FIG. 3, a methodology 120 for mapping UL ACK ID based upon a mode ofscheduling by an access node. If a determination is made that persistentscheduling is to be made that is not PDCCH allocated, nor is theallocation pertaining to a grouped PDCCH (block 122), then the mappingof the UL ACK ID is made explicitly in-band in the DL PDSCH with On-OffKeying (block 124). The access terminal can request a nonsequentialportion of the available cyclic shift ZC sequences in order to enhanceorthogonality due to other access nodes/communication paths present inthat sector or cell (block 126). If the determination in block 122 wasnegative, then dynamic scheduling (i.e., unicast PDCCH allocated) is thecase (block 128) and mapping is done implicitly for the UL ACK ID basedupon the resource allocation made by the PDCCH (block 130).

In FIG. 4, in yet another aspect, an access node 150 can reduce theoverhead involved in locating an UL ACK ID responsive to DL resourceallocation by having a module 152 for dynamically scheduling via avirtual resource block (VRB). A module 154 provides for unicastscheduling over a physical downlink control channel (PDCCH). A module156 provides for persistently scheduling via a physical downlink sharedchannel (PDSCH). A module 158 provides for receiving the multiplexed ULACK IDs. A module 160 provides for reserving requested cyclic shift ZCsequences for enhanced cell/sector orthogonality. A module 162 providesfor receiving On-Off Keying (OOK) by access terminals in response toin-band encoded persistently scheduling.

In FIG. 5, in yet a further aspect, an access terminal 170 canparticipate in reduced overhead involved in mapping an UL ACK IDresponsive to DL resource allocation by having a module 172 forreceiving dynamically scheduling via a virtual resource block (VRB). Amodule 174 provides for receiving unicast scheduling over a physicaldownlink control channel (PDCCH). A module 176 provides for receivingpersistently scheduling via a physical downlink shared channel (PDSCH).A module 178 provides for sending the UL ACK ID in accordance with themapping. A module 180 provides for requesting cyclic shift ZC sequencesfor enhanced cell/sector orthogonality. A module 182 provides forsending On-Off Keying (OOK) by access terminals in response to in-banddecoded persistently scheduling.

In FIG. 6, in another aspect, a communication system 200 that canencompass the communication system 10 of FIG. 1 includes support forinterfacing an evolved packet core 202 via an interface S4 with a legacyGeneral Packet Radio Service (GPRS) core 204, whose Serving GPRS SupportNode (SGSN) 206 is interfaced in turn by a Gb interface to a GlobalSystem for Mobile Communications (GSM)/Edge Radio Access Network (GERAN)208 and via an 1 u interface to a UTRAN 210. The S4 provides the userplane with related control and mobility support between GPRS Core 204and a 3GPP Anchor 212 of an Inter Access Stratum Anchor (IASA) 214 andis based on a Gn reference point as defined between SGSN 206 and GatewayGPRS Serving/Support Node (GGSN) (not shown). The IASA 214 also includesan system architecture evolved (SAE) anchor 216 interfaced to the 3GPPanchor 212 by an S5 b interface that provides the user plane withrelated control and mobility support. The 3GPP anchor 212 communicateswith an MME UPE 218 via interface S5 a. Mobility Management entity (MME)pertains to distribution of paging messages to the eNBs and User PlaneEntity (UPE) pertains to IP header compression and encryption of userdata streams, termination of U-plane packets for paging reasons, andswitching of U-plane for support of UE mobility. The MME UPE 218communicates via interface S1 to an evolved RAN 220 for wirelesslycommunicating with UE devices 222.

An S2 b interface provides the user plane with related control andmobility support between the SAE Anchor 216 and an evolved Packet DataGateway (ePDG) 224 of a wireless local access network (WLAN) 3GPP IPAccess component 226 that also includes a WLAN Access network (NW) 228.An SGi interface is the reference point between the Inter AS Anchor 216and a packet data network 230. Packet data network 230 may be anoperator external public or private packet data network or an intraoperator packet data network, e.g. for provision of IP MultimediaSubsystem (IMS) services. This SGi reference point corresponds to Gi andWi functionalities and supports any 3GPP and non-3GPP access systems. AnRx+interface provides communication between the packet data network 230and a policy and charging rules function (PCRF) 232, which in turncommunicates via an S7 interface to the evolved packet core 202. The S7interface provides transfer of (QoS) policy and charging rules from PCRF232 to Policy and Charging Enforcement Point (PCEP) (not shown). An S6interface (i.e., AAA interface) enables transfer of subscription andauthentication data for authenticating/authorizing user access byinterfacing the evolved packet core 202 to a home subscriber service(HSS) 234. An S2 a interface provides the user plane with relatedcontrol and mobility support between a trusted non 3GPP IP access 236and the SAE Anchor 216.

It should be appreciated that wireless communication systems are widelydeployed to provide various types of communication content such asvoice, data, and so on. These systems may be multiple-access systemscapable of supporting communication with multiple users by sharing theavailable system resources (e.g., bandwidth and transmit power).Examples of such multiple-access systems include code division multipleaccess (CDMA) systems, time division multiple access (TDMA) systems,frequency division multiple access (FDMA) systems, 3GPP LTE systems, andorthogonal frequency division multiple access (OFDMA) systems.

Generally, a wireless multiple-access communication system cansimultaneously support communication for multiple wireless terminals.Each terminal communicates with one or more base stations viatransmissions on the forward and reverse links. The forward link (ordownlink) refers to the communication link from the base stations to theterminals, and the reverse link (or uplink) refers to the communicationlink from the terminals to the base stations. This communication linkmay be established via a single-in-single-out, multiple-in-signal-out ora multiple-in-multiple-out (MIMO) system.

A MIMO system employs multiple (N_(T)) transmit antennas and multiple(N_(R)) receive antennas for data transmission. A MIMO channel formed bythe N_(T) transmit and N_(R) receive antennas may be decomposed intoN_(S) independent channels, which are also referred to as spatialchannels, where N_(S)≦min{N_(T), N_(R)}. Each of the N_(S) independentchannels corresponds to a dimension. The MIMO system can provideimproved performance (e.g., higher throughput and/or greaterreliability) if the additional dimensionalities created by the multipletransmit and receive antennas are utilized.

A MIMO system supports a time division duplex (TDD) and frequencydivision duplex (FDD) systems. In a TDD system, the forward and reverselink transmissions are on the same frequency region so that thereciprocity principle allows the estimation of the forward link channelfrom the reverse link channel. This enables the access point to extracttransmit beamforming gain on the forward link when multiple antennas areavailable at the access point.

Referring to FIG. 7, a multiple access wireless communication systemaccording to one aspect is illustrated. An access point 300 (AP)includes multiple antenna groups, one including 304 and 306, anotherincluding 308 and 310, and an additional including 312 and 314. In FIG.7, only two antennas are shown for each antenna group, however, more orfewer antennas may be utilized for each antenna group. Access terminal316 (AT) is in communication with antennas 312 and 314, where antennas312 and 314 transmit information to access terminal 316 over forwardlink 320 and receive information from access terminal 316 over reverselink 318. Access terminal 322 is in communication with antennas 306 and308, where antennas 306 and 308 transmit information to access terminal322 over forward link 326 and receive information from access terminal322 over reverse link 324. In a FDD system, communication links 318,320, 324 and 326 may use different frequency for communication. Forexample, forward link 320 may use a different frequency then that usedby reverse link 318.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access point. In theaspect, antenna groups each are designed to communicate to accessterminals in a sector, of the areas covered by access point 300.

In communication over forward links 320 and 326, the transmittingantennas of access point 300 utilize beamforming in order to improve thesignal-to-noise ratio of forward links for the different accessterminals 316 and 324. Also, an access point using beamforming totransmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access point transmitting through a single antenna to all its accessterminals.

An access point may be a fixed station used for communicating with theterminals and may also be referred to as an access point, a Node B, orsome other terminology. An access terminal may also be called an accessterminal, user equipment (UE), a wireless communication device,terminal, access terminal or some other terminology.

FIG. 8 is a block diagram of an aspect of a transmitter system 410 (alsoknown as the access point) and a receiver system 450 (also known asaccess terminal) in a MIMO system 400. At the transmitter system 410,traffic data for a number of data streams is provided from a data source412 to a transmit (TX) data processor 414.

In an aspect, each data stream is transmitted over a respective transmitantenna. TX data processor 414 formats, codes, and interleaves thetraffic data for each data stream based on a particular coding schemeselected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 430.

The modulation symbols for all data streams are then provided to a TXMIMO processor 420, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 420 then provides N_(T) modulationsymbol streams to N_(T) transmitters (TMTR) 422 a through 422 t. Incertain implementations, TX MIMO processor 420 applies beamformingweights to the symbols of the data streams and to the antenna from whichthe symbol is being transmitted.

Each transmitter 422 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 422 a through 422 t are thentransmitted from N_(T) antennas 424 a through 424 t, respectively.

At receiver system 450, the transmitted modulated signals are receivedby N_(R) antennas 452 a through 452 r and the received signal from eachantenna 452 is provided to a respective receiver (RCVR) 454 a through454 r. Each receiver 454 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 460 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 454 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. The RXdata processor 460 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 460 is complementary to thatperformed by TX MIMO processor 420 and TX data processor 414 attransmitter system 410.

A processor 470 periodically determines which pre-coding matrix to use(discussed below). Processor 470 formulates a reverse link messagecomprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 438, whichalso receives traffic data for a number of data streams from a datasource 436, modulated by a modulator 480, conditioned by transmitters454 a through 454 r, and transmitted back to transmitter system 410.

At transmitter system 410, the modulated signals from receiver system450 are received by antennas 424, conditioned by receivers 422,demodulated by a demodulator 440, and processed by a RX data processor442 to extract the reserve link message transmitted by the receiversystem 450. Processor 430 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage.

In an aspect, logical channels are classified into Control Channels andTraffic Channels. Logical Control Channels comprises Broadcast ControlChannel (BCCH), which is DL channel for broadcasting system controlinformation. Paging Control Channel (PCCH), which is DL channel thattransfers paging information. Multicast Control Channel (MCCH) which isPoint-to-multipoint DL channel used for transmitting MultimediaBroadcast and Multicast Service (MBMS) scheduling and controlinformation for one or several MTCHs. Generally, after establishing RRCconnection this channel is only used by UEs that receive MBMS (Note: oldMCCH+MSCH). Dedicated Control Channel (DCCH) is Point-to-pointbi-directional channel that transmits dedicated control information andused by UEs having an RRC connection. In aspect, Logical TrafficChannels comprises a Dedicated Traffic Channel (DTCH), which isPoint-to-point bi-directional channel, dedicated to one UE, for thetransfer of user information. In addition, a Multicast Traffic Channel(MTCH) for Point-to-multipoint DL channel for transmitting traffic data.

In an aspect, Transport Channels are classified into DL and UL. DLTransport Channels comprises a Broadcast Channel (BCH), Downlink SharedData Channel (DL-SDCH) and a Paging Channel (PCH), the PCH for supportof UE power saving (DRX cycle is indicated by the network to the UE),broadcasted over entire cell and mapped to PHY resources which can beused for other control/traffic channels. The UL Transport Channelscomprises a Random Access Channel (RACH), a Request Channel (REQCH), aUplink Shared Data Channel (UL-SDCH) and plurality of PHY channels. ThePHY channels comprise a set of DL channels and UL channels.

The DL PHY channels comprises: Common Pilot Channel (CPICH);Synchronization Channel (SCH); Common Control Channel (CCCH); Shared DLControl Channel (SDCCH); Multicast Control Channel (MCCH); Shared ULAssignment Channel (SUACH); Acknowledgement Channel (ACKCH); DL PhysicalShared Data Channel (DL-PSDCH); UL Power Control Channel (UPCCH); PagingIndicator Channel (PICH); Load Indicator Channel (LICH); The UL PHYChannels comprises: Physical Random Access Channel (PRACH); ChannelQuality Indicator Channel (CQICH); Acknowledgement Channel (ACKCH);Antenna Subset Indicator Channel (ASICH); Shared Request Channel(SREQCH); UL Physical Shared Data Channel (UL-PSDCH); Broadband PilotChannel (BPICH).

What has been described above includes examples of the various aspects.It is, of course, not possible to describe every conceivable combinationof components or methodologies for purposes of describing the variousaspects, but one of ordinary skill in the art may recognize that manyfurther combinations and permutations are possible. Accordingly, thesubject specification intended to embrace all such alterations,modifications, and variations that fall within the spirit and scope ofthe appended claims.

In particular and in regard to the various functions performed by theabove described components, devices, circuits, systems and the like, theterms (including a reference to a “means”) used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., a functional equivalent), even though not structurallyequivalent to the disclosed structure, which performs the function inthe herein illustrated exemplary aspects. In this regard, it will alsobe recognized that the various aspects include a system as well as acomputer-readable medium having computer-executable instructions forperforming the acts and/or events of the various methods.

In addition, while a particular feature may have been disclosed withrespect to only one of several implementations, such feature may becombined with one or more other features of the other implementations asmay be desired and advantageous for any given or particular application.To the extent that the terms “includes,” and “including” and variantsthereof are used in either the detailed description or the claims, theseterms are intended to be inclusive in a manner similar to the term“comprising.” Furthermore, the term “or” as used in either the detaileddescription of the claims is meant to be a “non-exclusive or”.

Furthermore, as will be appreciated, various portions of the disclosedsystems and methods may include or consist of artificial intelligence,machine learning, or knowledge or rule based components, sub-components,processes, means, methodologies, or mechanisms (e.g., support vectormachines, neural networks, expert systems, Bayesian belief networks,fuzzy logic, data fusion engines, classifiers . . . ). Such components,inter alia, can automate certain mechanisms or processes performedthereby to make portions of the systems and methods more adaptive aswell as efficient and intelligent. By way of example and not limitation,the evolved RAN (e.g., access point, eNode B) can infer or predict datatraffic conditions and opportunities for flexible DTX-DRX and makedeterminations of an implicit relinquishing of CQI resources by a UEdevice based on previous interactions with the same or like machinesunder similar conditions.

In view of the exemplary systems described supra, methodologies that maybe implemented in accordance with the disclosed subject matter have beendescribed with reference to several flow diagrams. While for purposes ofsimplicity of explanation, the methodologies are shown and described asa series of blocks, it is to be understood and appreciated that theclaimed subject matter is not limited by the order of the blocks, assome blocks may occur in different orders and/or concurrently with otherblocks from what is depicted and described herein. Moreover, not allillustrated blocks may be required to implement the methodologiesdescribed herein. Additionally, it should be further appreciated thatthe methodologies disclosed herein are capable of being stored on anarticle of manufacture to facilitate transporting and transferring suchmethodologies to computers. The term article of manufacture, as usedherein, is intended to encompass a computer program accessible from anycomputer-readable device, carrier, or media.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein, will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

1. A method for wireless communication, comprising: receiving a resourceallocation on a physical downlink control channel (PDCCH), the resourceallocation dynamically scheduling a user equipment (UE) for a datatransmission on downlink; and determining an uplink (UL) acknowledgement(ACK) resource based on the PDCCH, the UL ACK resource being associatedwith a time-varying cyclic shift of a base sequence used to send ACKinformation on uplink for the data transmission on the downlink.
 2. Themethod of claim 1, further comprising: sending the ACK information basedon a first cyclic shift of the base sequence in a first time period andbased on a second cyclic shift of the base sequence in a second timeperiod.
 3. The method of claim 1, wherein the UL ACK resource isassociated with a plurality of cyclic shifts of the base sequence thatvary across symbol periods.
 4. The method of claim 1, wherein the UL ACKresource is associated with a set of cyclic shifts of the base sequencefor a predetermined time interval.
 5. The method of claim 4, wherein theset of cyclic shifts includes non-sequential cyclic shifts among allcyclic shifts available for UL ACK resources.
 6. The method of claim 1,wherein the time-varying cyclic shift of the base sequence is determinedbased on a cell-specific hopping pattern.
 7. The method of claim 6,wherein adjacent cells are associated with different cell-specifichopping patterns to randomize interference.
 8. The method of claim 1,further comprising: receiving persistent scheduling for the UE; andreceiving explicit signaling of a second UL ACK resource for the UE, thesecond UL ACK resource being used by the UE to send ACK information fordata transmissions covered by the persistent scheduling.
 9. The methodof claim 1, further comprising: generating at least one localizedfrequency division multiplexing (LFDM) symbol comprising the ACKinformation sent based on the UL ACK resource.
 10. The method of claim1, wherein the UL ACK resource is further associated with at least onefrequency resource, or at least one time resource, or at least one coderesource, or a combination thereof, for sending the ACK information. 11.The method of claim 1, wherein the base sequence comprises a Zadoff-Chusequence.
 12. An apparatus for wireless communication, comprising: meansfor receiving a resource allocation on a physical downlink controlchannel (PDCCH), the resource allocation dynamically scheduling a userequipment (UE) for a data transmission on downlink; and means fordetermining an uplink (UL) acknowledgement (ACK) resource based on thePDCCH, the UL ACK resource being associated with a time-varying cyclicshift of a base sequence used to send ACK information on uplink for thedata transmission on the downlink.
 13. The apparatus of claim 12,further comprising: means for sending the ACK information based on afirst cyclic shift of the base sequence in a first time period and basedon a second cyclic shift of the base sequence in a second time period.14. The apparatus of claim 12, wherein the UL ACK resource is associatedwith a plurality of cyclic shifts of the base sequence that vary acrosssymbol periods.
 15. The apparatus of claim 12, wherein the time-varyingcyclic shift of the base sequence is determined based on a cell-specifichopping pattern.
 16. The apparatus of claim 12, further comprising:means for receiving persistent scheduling for the UE; and means forreceiving explicit signaling of a second UL ACK resource for the UE, thesecond UL ACK resource being used by the UE to send ACK information fordata transmissions covered by the persistent scheduling.
 17. Anapparatus for wireless communication, comprising: at least one processorconfigured to receive a resource allocation on a physical downlinkcontrol channel (PDCCH), the resource allocation dynamically schedulinga user equipment (UE) for a data transmission on downlink, and todetermine an uplink (UL) acknowledgement (ACK) resource based on thePDCCH, the UL ACK resource being associated with a time-varying cyclicshift of a base sequence used to send ACK information on uplink for thedata transmission on the downlink.
 18. The apparatus of claim 17,wherein the at least one processor is configured to send the ACKinformation based on a first cyclic shift of the base sequence in afirst time period and based on a second cyclic shift of the basesequence in a second time period.
 19. The apparatus of claim 17, whereinthe UL ACK resource is associated with a plurality of cyclic shifts ofthe base sequence that vary across symbol periods.
 20. The apparatus ofclaim 17, wherein the time-varying cyclic shift of the base sequence isdetermined based on a cell-specific hopping pattern.
 21. The apparatusof claim 17, wherein the at least one processor is configured to receivepersistent scheduling for the UE, and to receive explicit signaling of asecond UL ACK resource for the UE, the second UL ACK resource being usedby the UE to send ACK information for data transmissions covered by thepersistent scheduling.
 22. A computer program product, comprising: anon-transitory computer-readable medium comprising: code for causing atleast one processor to receive a resource allocation on a physicaldownlink control channel (PDCCH), the resource allocation dynamicallyscheduling a user equipment (UE) for a data transmission on downlink,and code for causing the at least one processor to determine an uplink(UL) acknowledgement (ACK) resource based on the PDCCH, the UL ACKresource being associated with a time-varying cyclic shift of a basesequence used to send ACK information on uplink for the datatransmission on the downlink.
 23. A method for wireless communication,comprising: sending a resource allocation on a physical downlink controlchannel (PDCCH) to a user equipment (UE), the resource allocationdynamically scheduling the UE for a data transmission on downlink; anddetermining an uplink (UL) acknowledgement (ACK) resource based on thePDCCH, the UL ACK resource being associated with a time-varying cyclicshift of a base sequence used by the UE to send ACK information onuplink for the data transmission on the downlink.
 24. The method ofclaim 23, further comprising: receiving the ACK information sent by theUE based on a first cyclic shift of the base sequence in a first timeperiod and based on a second cyclic shift of the base sequence in asecond time period.
 25. The method of claim 23, wherein the UL ACKresource is associated with a plurality of cyclic shifts of the basesequence that vary across symbol periods.
 26. The method of claim 23,wherein the UL ACK resource is associated with a set of cyclic shifts ofthe base sequence for a predetermined time interval.
 27. The method ofclaim 23, wherein the time-varying cyclic shift of the base sequence isdetermined based on a cell-specific hopping pattern.
 28. The method ofclaim 23, further comprising: sending persistent scheduling for the UE;and sending explicit signaling of a second UL ACK resource for the UE,the second UL ACK resource being used by the UE to send ACK informationfor data transmissions covered by the persistent scheduling.
 29. Themethod of claim 23, wherein the UL ACK resource is further associatedwith at least one frequency resource, or at least one time resource, orat least one code resource, or a combination thereof, for sending ACKinformation.
 30. An apparatus for wireless communication, comprising:means for sending a resource allocation on a physical downlink controlchannel (PDCCH) to a user equipment (UE), the resource allocationdynamically scheduling the UE for a data transmission on downlink; andmeans for determining an uplink (UL) acknowledgement (ACK) resourcebased on the PDCCH, the UL ACK resource being associated with atime-varying cyclic shift of a base sequence used by the UE to send ACKinformation on uplink for the data transmission on the downlink.
 31. Theapparatus of claim 30, further comprising: means for receiving the ACKinformation sent by the UE based on a first cyclic shift of the basesequence in a first time period and based on a second cyclic shift ofthe base sequence in a second time period.
 32. The apparatus of claim30, wherein the UL ACK resource is associated with a plurality of cyclicshifts of the base sequence that vary across symbol periods.
 33. Theapparatus of claim 30, wherein the time-varying cyclic shift of the basesequence is determined based on a cell-specific hopping pattern.
 34. Theapparatus of claim 30, further comprising: means for sending persistentscheduling for the UE; and means for sending explicit signaling of asecond UL ACK resource for the UE, the second UL ACK resource being usedby the UE to send ACK information for data transmissions covered by thepersistent scheduling.
 35. The apparatus of claim 30, wherein the UL ACKresource is further associated with at least one frequency resource, orat least one time resource, or at least one code resource, or acombination thereof, for sending ACK information.
 36. An apparatus forwireless communication, comprising: at least one processor configured tosend a resource allocation on a physical downlink control channel(PDCCH) to a user equipment (UE), the resource allocation dynamicallyscheduling the UE for a data transmission on downlink, and to determinean uplink (UL) acknowledgement (ACK) resource based on the PDCCH, the ULACK resource being associated with a time-varying cyclic shift of a basesequence used by the UE to send ACK information on uplink for the datatransmission on the downlink.
 37. The apparatus of claim 36, wherein theat least one processor is configured to receive the ACK information sentby the UE based on a first cyclic shift of the base sequence in a firsttime period and based on a second cyclic shift of the base sequence in asecond time period.
 38. The apparatus of claim 36, wherein the UL ACKresource is associated with a plurality of cyclic shifts of the basesequence that vary across symbol periods.
 39. The apparatus of claim 36,wherein the time-varying cyclic shift of the base sequence is determinedbased on a cell-specific hopping pattern.
 40. The apparatus of claim 36,wherein the at least one processor is configured to send persistentscheduling for the UE and to send explicit signaling of a second UL ACKresource for the UE, the second UL ACK resource being used by the UE tosend ACK information for data transmissions covered by the persistentscheduling.
 41. The apparatus of claim 36, wherein the UL ACK resourceis further associated with at least one frequency resource, or at leastone time resource, or at least one code resource, or a combinationthereof, for sending ACK information.
 42. A computer program product,comprising: a non-transitory computer-readable medium comprising: codefor causing at least one processor to send a resource allocation on aphysical downlink control channel (PDCCH) to a user equipment (UE), theresource allocation dynamically scheduling the UE for a datatransmission on downlink, and code for causing the at least oneprocessor to determine an uplink (UL) acknowledgement (ACK) resourcebased on the PDCCH, the UL ACK resource being associated with atime-varying cyclic shift of a base sequence used by the UE to send ACKinformation on uplink for the data transmission on the downlink.